Four engagement types covering the full spectrum of vineyard biological risk — from annual health monitoring through to pre-purchase enhanced due diligence for high-value transactions.
Every BARS engagement begins with a signed Engagement Proposal confirming scope, fees, and visit timing. The engagement type determines the number of field visits, the diagnostic scope, the trunk disease assessment tier, and the outputs produced. Select the engagement that matches your context — or contact BARS Institute if you are unsure which applies.
All assessments include GLRaV-3 composite pool screening as standard. Additional virus targets (GRBV, GPGV) are available as separately scoped add-ons — see below.
| Feature | Health Certificate | BARS Report | Annual Monitor | Pre-Purchase Enhanced Due Diligence |
|---|---|---|---|---|
| Field visits | 1 | 1 | 1 | 2 |
| GLRaV-3 scope | Composite pool survey | Composite pool survey; Dorfman inversion prevalence estimation | Re-survey; updated I₀ and BVS; spread trajectory reconciliation against prior-year 90% simulation interval | Full BARS Report scope plus individual vine RT-qPCR confirmation on all positive composite bays |
| Trunk disease scope | Tier 1 visual survey — D₀ recorded; BGS with wide uncertainty interval | Tier 1 standard; Tier 2 pruning-cut wood inspection available as dormancy add-on — narrows BGS uncertainty interval and infers pathogen class | Updated Tier 1 visual survey; BGS progression reconciled against prior model trajectory | Tier 3 qPCR — species-level pathogen confirmation; narrow uncertainty interval; standard scope |
| Primary output |
Health Certificate — no GLRaV-3 detected; trunk disease visual indicators recorded
Auto-upgrades to full BARS Report if any positive pool is found — no additional field visit required.
|
BVS · BGS · ESS · NPV impairment P5/P50/P95 (virus and GTD) · Replant trigger year · Intervention value · Block tail-risk contribution (multi-block) | Annual Monitor Report — updated BVS and BGS; Management Regime Divergence status; revised NPV impairment disclosed to lender where divergence detected | Enhanced Due Diligence Report — all BARS Report outputs plus species-level pathogen confirmation, vine-level co-occurrence data, and narrow uncertainty intervals across all figures |
| Prerequisite | — | — | Prior BARS Report at the same property | — |
| Typical use case | Annual monitoring of known-healthy blocks; lender covenant compliance | New engagements; financing and security review; property transaction; refinancing or loan renewal; impairment indicator assessment; valuation requiring biological condition evidence; change of ownership or entity; covenant establishment; any engagement where independent biological risk evidence is required. | Year-on-year biological risk tracking; lender covenant monitoring following a base-year BARS Report | Pre-purchase due diligence; legal and insurance contexts; high-value transactions requiring maximum biological certainty |
The Health Certificate is a single-visit screening engagement designed for blocks with no known infection history. It confirms absence of GLRaV-3 at the stated detection confidence and records trunk disease visual indicators across all vine positions. It is the appropriate engagement for lender covenant monitoring of known-healthy blocks and for properties seeking annual confirmation of clean biological status.
If any positive GLRaV-3 composite pool is found during the visit, the engagement automatically upgrades to a full BARS Report using the RT-qPCR and Tier 1 trunk disease data already collected. No additional field visit is required. The BGS in an auto-upgraded report carries a Tier 1 wide uncertainty interval, disclosed in the report.
The BARS Report is the core engagement for new assessments, blocks over ten years old, and any context requiring quantified biological impairment evidence. It produces the full suite of BARS financial outputs — NPV impairment, replant trigger year, intervention value, and block-level tail-risk contribution for multi-block properties — alongside the independently derived BVS and BGS current-condition scores.
A single growing-season visit is the standard configuration. Where Tier 2 trunk disease assessment is required, a dormancy visit is added to perform pruning-cut wood inspection — narrowing the BGS uncertainty interval and enabling pathogen class inference from internal wood symptom patterns.
The Annual Monitor re-surveys a property that has received a base-year BARS Report, updating BVS and BGS and reconciling observed disease progression against the prior-year model projection. Where the newly observed I₀ exceeds the P95 upper bound of the prior-year 90% simulation interval, a Management Regime Divergence is declared — triggering a formal review of the vector-pressure multiplier and recalculation of NPV impairment under the revised regime.
This reconciliation structure means the base-year BARS Report does not assume stated management will be followed. It quantifies impairment risk under the stated regime and prices the consequence of divergence transparently when it occurs. Lenders receive a direct report of divergence findings and revised impairment figures.
The Pre-Purchase Enhanced Due Diligence engagement is the highest-precision biological assessment available for vineyard assets. It combines all BARS Report outputs with individual vine RT-qPCR confirmation on every positive composite bay — narrowing the uncertainty interval around vine-level prevalence — and Tier 3 qPCR trunk disease assessment providing species-level pathogen confirmation.
This engagement is designed for transaction contexts where maximum biological certainty is required: pre-purchase due diligence, legal disputes, insurance claims, and high-value transactions where latent impairment risk must be characterised at the narrowest achievable uncertainty interval. The two-visit protocol covers both dormancy (trunk disease) and growing season (virus).
All assessments include GLRaV-3 RT-qPCR screening as standard. The following virus targets are available as separately scoped add-ons where specified in the signed Engagement Proposal. Tissue collection requirements and seasonal timing constraints differ from the GLRaV-3 standard — contact BARS Institute before engagement to confirm scope.
Available as a biosecurity surveillance add-on for clients seeking to confirm absence in imported material or newly established blocks, or where symptoms consistent with GRBV have been observed. Requires leaf blade tissue collected December–February. Petiole tissue and collection outside this window are not approved for GRBV assessment.
Where GRBV is detected, financial impairment outputs carry a heightened parameter uncertainty disclosure — no NZ-calibrated α or β₀ values are currently available. Results are reported separately from GLRaV-3 impairment figures.
Available for Pinot Gris and Chardonnay blocks where mottling or deformation symptoms are present. Requires a separate spring shoot visit during active shoot growth (September–November). Results are reported as presence/absence only — financial impairment modelling is not applied to GPGV at this time due to insufficient NZ-specific pathogenicity and yield-loss data.
Collection outside the September–November window is not recommended and will be noted as a limitation in the report.
Tell us about the property, blocks, and context. We'll confirm scope and fee within one business day.
Start an enquiry →BARS outputs are decision-support evidence for engaging professionals. They do not replace a registered valuation, accounting opinion, or credit decision.